From: Matthew Wilcox <matthew@wil.cx>
Date: Thu, 6 Dec 2007 16:18:49 +0000 (-0500)
Subject: Add lock_page_killable
X-Git-Tag: v2.6.25-rc1~1125^2~8
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2687a3569e40b1302f96698bcd6329aeb0ce3dd2;p=linux-2.6

Add lock_page_killable

This routine is like lock_page, but can be interrupted by a fatal signal

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
---

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index db8a410ae9..4b62a10562 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -157,6 +157,7 @@ static inline pgoff_t linear_page_index(struct vm_area_struct *vma,
 }
 
 extern void FASTCALL(__lock_page(struct page *page));
+extern int FASTCALL(__lock_page_killable(struct page *page));
 extern void FASTCALL(__lock_page_nosync(struct page *page));
 extern void FASTCALL(unlock_page(struct page *page));
 
@@ -170,6 +171,19 @@ static inline void lock_page(struct page *page)
 		__lock_page(page);
 }
 
+/*
+ * lock_page_killable is like lock_page but can be interrupted by fatal
+ * signals.  It returns 0 if it locked the page and -EINTR if it was
+ * killed while waiting.
+ */
+static inline int lock_page_killable(struct page *page)
+{
+	might_sleep();
+	if (TestSetPageLocked(page))
+		return __lock_page_killable(page);
+	return 0;
+}
+
 /*
  * lock_page_nosync should only be used if we can't pin the page's inode.
  * Doesn't play quite so well with block device plugging.
diff --git a/mm/filemap.c b/mm/filemap.c
index 188cf5fd3e..ac8f690d28 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -173,6 +173,12 @@ static int sync_page(void *word)
 	return 0;
 }
 
+static int sync_page_killable(void *word)
+{
+	sync_page(word);
+	return fatal_signal_pending(current) ? -EINTR : 0;
+}
+
 /**
  * __filemap_fdatawrite_range - start writeback on mapping dirty pages in range
  * @mapping:	address space structure to write
@@ -577,6 +583,14 @@ void fastcall __lock_page(struct page *page)
 }
 EXPORT_SYMBOL(__lock_page);
 
+int fastcall __lock_page_killable(struct page *page)
+{
+	DEFINE_WAIT_BIT(wait, &page->flags, PG_locked);
+
+	return __wait_on_bit_lock(page_waitqueue(page), &wait,
+					sync_page_killable, TASK_KILLABLE);
+}
+
 /*
  * Variant of lock_page that does not require the caller to hold a reference
  * on the page's mapping.